The present disclosure relates to passive millimeter wave imaging systems, and more specifically, to contrast phantoms for such systems.
Unlike X-ray systems with their ionizing radiation, and active Microwave systems which bathe an object in RF energy, passive millimeter-wave (PMMW) imaging systems read the natural thermal energy in an environment much like an infrared camera. However, infrared wavelengths are too short to pass through clothing so longer wavelengths are chosen such as 3 mm (or from about 80 to 100 GHz).
Heat coming off a human body is interrupted by occluding objects which have a temperature of their own, or reflect other temperatures in the environment, giving rise to contrast that can imaged by a millimeter wave camera or radiometer.